In a factory where a screw tightening operation is performed by using a tool, the screw tightening operation has been managed by controlling a tightening torque by the tool and transmitting a signal for the completion of tightening at a required torque to a management device. In this case, it is preferable to use wireless communications as shown in Japanese Patent No. 2983124 and Japanese Patent Application Publication No. 2000-024945 rather than wire communications because the wire communications negatively affects the convenience of the tool.
However, there is possibility that there are various kinds of environmental noises, such as wireless LAN and the like, in the factory, thereby causing communications errors due to such noises during the wireless communications. However, conventionally, a wireless communications frequency has to be fixed and cannot be changed in the field and, thus, it is required to make the wireless communications frequency changeable.
Accordingly, there has been proposed to set and change a wireless communications frequency by a DIP switch. However, if many setting switches, including a DIP switch and the like, are provided with the tool, there can be a high possibility of a tool operation failure due to intrusion of foreign material such as iron powder and the like depending on the surrounding environment.
Moreover, in order to eliminate the necessity of providing setting switches for the tool, there has been proposed to use a personal computer (hereinafter, referred to as PC) to set a wireless communications frequency or the ID number of a transceiver by the PC. However, in such a case, when a plurality of tools is used in the factory, each of the tools needs to be connected to the PC to change the settings of all the tools, thus entailing an extremely poor working efficiency.